1. Field of the Invention
The present invention is related to the field of mining and, more particularly, to rolls of polymeric mesh or grid material for support of mining tunnels, which rolls are self-resistant to unrolling, a method of making such rolls, and a method of using and installing the same including installation of the rolls with a mining machine.
2. Description of the Related Art
Mining practices have long included the use of a continuous miner having integrated roof bolters to support the ceiling or roof of a mine tunnel both during and after a cutting operation. In addition, supplemental roof supports in the form of continuous lengths or sheets of metallic mesh or wire grids have been installed on the mine tunnel roof. While the roof bolts provide the workers with their primary protection, the mesh mats or grids are used to support loose strata and thereby provide secondary protection against material that may fall between the roof bolts.
Installation of the supplemental roof support meshes or grids may be performed manually, either while the continuous miner is in place or after the continuous miner has been withdrawn from the tunnel that is to be supported. Meshing mine tunnels with welded metal wire or mesh mats has always been a very time consuming and dangerous task as they are heavy to manipulate and, when damaged, can inflict puncture injuries on the installers.
The elimination of wire meshes or mats in favor of rolled polymeric mesh materials represented an improvement for workers in the mining industry as the polymeric mesh materials enable the mine roof to be meshed without the need to handle wire panels. In addition, mechanized methods of meshing the roof further ease the burden on mine workers.
Many systems have been developed that allow polymeric mesh rolls to be held and controlled by attaching a deployment apparatus to the continuous miner or other mining machine. One such system is disclosed in U.S. Pat. No. 5,816,750 (“the '750 patent”), which is commonly owned by the assignee of the present application and is hereby expressly incorporated by reference as if fully set forth herein.
The '750 patent discloses a grid layout system including a grid dispenser for rolls of polymeric mesh or grid material. The grid dispenser is mounted on the boom of the continuous miner and, in response to tension on the roll created by forward and rearward movement of the continuous miner during a cutting operation, incrementally dispenses or retracts the polymeric mesh or grid material above the continuous miner which is then bolted to the mine tunnel roof. To prevent the roll from unwinding when the continuous miner stops, the grid dispenser of the '750 patent is provided with a motor that exerts a retractive force on the roll which holds the mesh material under tension in the dispenser.
As noted, the grid layout system disclosed in the '750 patent requires a grid dispenser attached to the mining machine, such that the machine must be modified to include the dispenser. Therefore, a need exists for a method of deploying and controlling the unrolling of mesh rolls during installation of such rolls for mining roof support that does not require a special deployment device attached to the mining machine but which can use the mining machine's existing structure to hold the roll. A need also exists for a method of deploying mesh rolls that can accommodate not only horizontal orientations, but vertical and diagonal orientations as found on mine walls or other surfaces.